Method of storing photoresist coated substrates and semiconductor substrate container arrangement

ABSTRACT

A method for manufacturing a semiconductor device includes forming a forming a photoresist layer over a semiconductor substrate and selectively exposing the photoresist layer to actinic radiation. After selectively exposing the photoresist layer to actinic radiation, storing the semiconductor substrate in a semiconductor substrate container under an ambient of extreme dry clean air or inert gas. The method also includes after the storing the semiconductor substrate, performing a first heating of the photoresist layer.

PRIORITY CLAIM AND CROSS-REFERENCE

This application is a divisional application of U.S. application Ser.No. 16/697,136, filed Nov. 26, 2019, which claims priority to U.S.Provisional Application No. 62/773,928 filed on Nov. 30, 2018, entitled“METHOD OF STORING PHOTORESIST COATED SUBSTRATES AND STORAGE CONTAINERARRANGEMENT,” the entire disclosures of each or which are incorporatedherein by reference.

BACKGROUND

As consumer devices have gotten smaller and smaller in response toconsumer demand, the individual components of these devices havenecessarily decreased in size as well. Semiconductor devices, which makeup a major component of devices such as mobile phones, computer tablets,and the like, have been pressured to become smaller and smaller, with acorresponding pressure on the individual devices (e.g., transistors,resistors, capacitors, etc.) within the semiconductor devices to also bereduced in size.

One enabling technology that is used in the manufacturing processes ofsemiconductor devices is the use of photosensitive materials. Suchmaterials are applied to a surface and then exposed to an energy that,has itself been patterned. Such an exposure modifies the chemical andphysical properties of the exposed regions of the photosensitivematerial. This modification, along with the lack of modification inregions of the photosensitive that were not exposed, can be exploited toremove one region without removing the other.

As the semiconductor device sizes continue to shrink, for example below20 nanometer (nm) nodes, traditional lithography technologies haveoptical restrictions, which leads to resolution issues and may notachieve the desired lithography performance. Extreme ultravioletlithography (EUVL) has been developed to form smaller semiconductordevice feature size and increase device density on a semiconductorwafer. Because metals have high extreme ultraviolet (EUV) absorbance,metal-containing photoresists have been developed to provide improvedEUVL. Metal-containing photoresists, after being exposed, aresusceptible to water absorption which may negatively affect the criticaldimension of the photoresist patterns on a wafer, especially when thereis a delay between a first time the wafer coated with metal-containingphotoresist is exposed to EUV to create a pattern and a second time thepost-exposure bake (PEB) is performed on the wafer. An efficienttechnique to prevent water contamination of metal-containingphotoresists is desirable.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is best understood from the following detaileddescription when read with the accompanying figures. It is emphasizedthat, in accordance with the standard practice in the industry, variousfeatures are not drawn to scale and are used for illustration purposesonly. In fact, the dimensions of the various features may be arbitrarilyincreased or reduced for clarity of discussion.

FIG. 1A illustrates a rear view of an exemplary semiconductor substratecontainer containing semiconductor wafers in accordance with someembodiments of the present disclosure.

FIG. 1B illustrates a side view of an exemplary semiconductor substratecontainer of a storage system in accordance with some embodiments of thepresent disclosure.

FIG. 2 illustrates a process flow tor patterning wafers of asemiconductor substrate container in accordance with some embodiments ofthe present disclosure.

FIG. 3 illustrates a plot of relative humidity versus purge time in afront opening unified pod (FOUP) in accordance with some embodiments ofthe present disclosure.

FIGS. 4A and 4B illustrate the change in critical dimension of anexposed metal photoresist after storage in a FOUP without and withpurging the FOUP in accordance with some embodiments of the presentdisclosure.

FIG. 5 illustrates a flow-diagram of a process for manufacturing asemiconductor device in accordance with some embodiments of the presentdisclosure.

FIGS. 6A and 6B illustrate an apparatus for purging the semiconductorsubstrate container of water vapor in accordance with some embodimentsof the present disclosure.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct, contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be lit direct contact.In addition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature/s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly. In addition, the term“being made of” may mean either “comprising” or “consisting of.” In thepresent disclosure, a phrase “one of A, B and C” means “A, B and/or C”(A, B, C, A and B, A and C, B and C, or A, B and C), and does not meanone element from A, one element from B and one element from C, unlessotherwise described.

As the semiconductor device sizes continue to shrink, EUV radiation isused in an EUVL system to pattern the wafers. Metals show high EUVabsorption and thus metal-containing photoresists have been developed toprovide improved EUVL. However, the exposed metal-containingphotoresists are susceptible to water vapor that may exist in theenvironment, e.g., in the air, and may interact with the exposedmetal-containing photoresists, and deteriorate the exposedmetal-containing photoresists in time. Thus, if a wafer covered with ametal-containing photoresists is exposed to EUV to project a layout ontothe surface of the wafer and the wafer is kept in an environmentcontaining water vapor, the exposed metal-containing photoresists maydeteriorate and affect the critical dimension (CD) of the projectedlayout.

In some embodiments, the next process step after projecting a layoutonto the surface of the wafer with EUV is the post-exposure bake. Theexposed wafers having projected layouts on them may be stored inside asemiconductor substrate container, e.g., a FOUP, before being sent tothe post-exposure bake operation. The FOUP with the exposed wafers maybe stored for a storage time up to a few days, e.g., two days, beforebeing sent to the post-exposure bake operation. In some embodiments,when water vapor exists in the FOUP the water vapor affects the CD ofthe projected layout on the wafers. In some embodiments, purging thewater vapor from the FOUP environment after the exposed wafers areloaded in the FOUP and sealing the purged FOUP before storing foe FOUPremoves the water vapor from the FOUP environment and prevents the CDchange of the exposed wafers in the FOUP due to storing the FOUP for upto at least a few days.

FIG. 1A illustrates a rear view of an exemplary semiconductor substratecontainer containing semiconductor wafers in accordance with someembodiments of the present disclosure. As shown in FIG. 1A, a storagesystem 10 includes a semiconductor substrate container 12 with a handle16 and containing semiconductor wafers 27. The semiconductor substratecontainer 12 is supported on a surface 24 of a platform 22. In someembodiments, the platform 22 is a location for storing and/or sealingthe semiconductor substrate container 12. When the platform 22 is thelocation for sealing the semiconductor substrate container 12, thestorage system 10 includes a gas inlet 20 for introducing an extremeclean dry air or an inert gas into the semiconductor substrate container12 and a gas outlet 25 for allowing gas, including extreme clean dryair, inert gas, or water vapor to exit foe semiconductor substratecontainer 12 during a purging operation.

In some embodiments, an inert gas source or a source for extreme cleandry air is connected to the gas inlet 20. In some embodiments, a gaspurifier 40 is connected in line with the gas inlet 20. In someembodiments, the gas purifier 40 that is connected to the gas inlet 20is an automatically re-generable purifier, such as an Ambient Temp PS22Automatically Re-generable Purifier manufactured by SAES Pure Gas. Insome embodiments, the gas purifier is configured to provide a purifiedgas containing less than 1 ppb impurities and less than 1% relativehumidity.

In some embodiments, a sensor 30 measures the humidity of gas passingthrough the gas outlet 25. In some embodiments, extreme clean dry air orinert gas flows into the semiconductor substrate container 12 throughthe lower portion 14 of the semiconductor substrate container 12 and thesemiconductor substrate container 12 is purged until the relativehumidity of the gas exiting the semiconductor substrate container 12through the gas outlet 25 has a relative humidity below a thresholdvalue as measured by the sensor 30. In some embodiments, the thresholdvalue is in a range of relative humidity values between 0.1% and 1%relative humidity. When the relative humidity drops below the thresholdvalue, the gas flow is shut off and the gas outlet 25 and the gas inlet20 of the semiconductor substrate container 12 are sealed. In someembodiments, when the sealed semiconductor substrate container 12 isstored between process steps, the pressure of extreme clean dry air orinert gas in the semiconductor substrate container 12 is kept about 130kPa. In some embodiments, the pressure inside the semiconductorsubstrate container 12, e.g., the FOUP, after being sealed is about thesame as the ambient pressure, e.g., the atmospheric pressure.

FIG. 1B illustrates a side view of an exemplary semiconductor substratecontainer of a storage system in accordance with some embodiments of thepresent disclosure. The storage system 10 includes the semiconductorsubstrate container 12 that may be a front opening unified pod (FOUP).The FOUP has a door 15, which is opened and closed to introduce orremove substrates (e.g., wafers) from the FOUP. In some embodiments, thedoor 15 may tightly seal the container and to prevent gas exchange toand from the semiconductor substrate container 12 via the door 15. Asdescribed, the storage system 10 also includes the gas inlet 20 forintroducing extreme clean dry air or an inert gas into the semiconductorsubstrate container 12, and includes the gas outlet 25 that allows gas,including extreme clean dry air, inert gas, and water vapor to exit thesemiconductor substrate container 12 during the purging operation. Insome embodiments, when the relative humidity drops below the thresholdvalue, the gas outlet 25, the gas inlet 20, and the door 15 of thesemiconductor substrate container 12 are sealed.

FIG. 2 illustrates a process flow for patterning wafers in accordancewith some embodiment of the disclosure. In some embodiments, asemiconductor substrate, such as the wafer 27 of FIG. 1A, is coatedaround the edges with a protective composition in an EC (edge coating)operation 202. The protective composition may include a polymer with anacid-labile group (ALG) and a thermal acid generator (TAG) or aphoto-acid generator (PAG) in a solvent. When the TAG or PAG isactivated, an acid is released, which cleaves rise ALG on the polymerthat causes the polymer to cross-link and cure, e.g., harden. In someembodiments, the solvent of the protective composition is the propyleneglycol methyl ether acetate (PGMEA). In some embodiments, the operation202 protects the substrate edge and to prevent the metal-containingphotoresist from spilling from the wafer edge and contaminating processlocations that the wafer 27 is transferred to during the subsequentprocess steps. The protective composition is applied to edges of thesemiconductor substrate in some embodiments to protect the edges, sides,and backside of the semiconductor substrate (e.g., wafer). Theprotective composition is baked in an edge coating (EC) bake operation204 and then the metal-containing photoresist (MePR) is coated on a topsurface of the semiconductor wafer 27 in a photoresist coating operation(MePR coat) 206. The metal-containing photoresist is described in moredetail below. Following the application of metal-containing photoresistto the surface of wafer 27. the protective composition is removed in anEC stripping operation 208, and then the photoresist undergoes apost-application bake (PAB) operation 210, also known as a pre-exposurebake or soft bake to cure the metal-containing photoresist. In someembodiments, the pre-exposure bake is performed at a temperature varyingfrom about 40° C. to about 120° C. for about 10 seconds to about 10minutes.

In some embodiments, the photolithography tool is a laser scanner, inother embodiments, the photolithography tool is an extreme ultravioletlithography (EUVL) tool. In some embodiments, the semiconductorsubstrate container 12 is transferred to a load port at T-load portoperation 212 where the semiconductor substrate container 12 and thewafers in the semiconductor substrate container 12 are transferred toanother process location. In some embodiments, the other processlocation is a process location for exposing the wafer 27 and performinglithography. In some embodiments, the pre-exposure bake is performed ata temperature varying from about 40° C. to about 120° C. for about 10seconds to about 10 minutes.

Next, the metal-containing photoresist is selectively exposed to actinicradiation in the photolithography tool in an exposure (EXP) operation214 to form a latent pattern in the photoresist layer, and then thewafer 27 having the exposed metal-containing photoresist is loaded intothe semiconductor substrate container 12, e.g., a front opening unifiedpod (FOUP), and the FOUP is purged with an extreme clean dry air (xCDA)or inert gas in the xCDA Purged FOUP operation 216. As described, insome embodiments, the semiconductor substrate container 12 is a FOUP andthe FOUP is seated after the xCDA Purged FOUP operation 216. The xCDAPurged FOUP operation 216, which includes purging the inside environmentof the semiconductor substrate container 12, e.g., the FOUP, and thewafers 27 inside the semiconductor substrate container 12 with extremeclean dry air or inert gas is described above with respect to FIGS. 1Aand 1B. In some embodiments, a time interval exists between the exposureoperation 214 and the next operation, the post-exposure bake (PEB)operation 218 and during the time interval (e.g., a storage period or aduration of storing) the semiconductor substrate container 12, e.g., theFOUP, is stored in a storage location (not shown). In some embodiments,there is an operation similar to the T-load port operation 212 afterxCDA Purged FOUP operation 216 that transfers the semiconductorsubstrate container 12 to the storage location and then after thestorage period transfers the semiconductor substrate container 12 fromthe storage location to a location for the next operation, which is apost-exposure bake (PEB) operation 218.

After the storage period, which may range from a few minutes to a fewdays, the semiconductor substrates, e.g., wafers 27, are removed fromthe semiconductor substrate container 12 (the FOUP) and are heated inthe post-exposure bake (PEB) operation 218. In some embodiments, thesemiconductor substrates are heated at a temperature ranging from about50° C. to about 170° C. for about 20 seconds to about 120 seconds duringthe post-exposure bake. Then, the wafers 27 are again coated with aprotective coating in an edge coating operation 220, in someembodiments, where in addition to wafer edges, sides, and backside ofthe wafers 27 may also be protected by the protective coating. Theprotective coating is baked in the edge coat (EC) baking operation 222.The baked edge coating prevents the metal-containing photoresist and thesolvent of the metal-containing photoresist from spilling over the waferedges contaminating other process locations that the wafer 27 istransferred to during the subsequent process steps.

Next, the photoresist is developed to generate a pattern in lirephotoresist layer in a development operation 224. In some embodiments,the development operation is a negative tone development (NTD) operationthat develops portions of the photoresist layer at locations that arenot exposed. In some embodiments, the development operation 224 is apositive tone development operation that develops portions of thephotoresist layer at locations that are exposed. Subsequently, theprotective coating is removed in edge coat (EC) stripping operation 226,and the patterned photoresist-coated substrate is heated to dry thepatterned photoresist-coated wafer 27 in a baking operation 228operation (Bake).

In some embodiments, the edge coat baiting operations 204 arid 222 areperformed at a temperature and time sufficient to cure and dry theprotective layers. In some embodiments, the protective layers are heatedat a temperature of between about 40° C. and about 200° C. for about 10seconds to about 10 minutes. In some embodiments, the photoresist layeris also heated at the post-application bake operation 210 at atemperature of between about 40° C. and about 200° C. for about 10seconds to about 10 minutes.

FIG. 3 illustrates a plot 300 of relative humidity 302 versus purge time304 in a FOUP, e.g., the semiconductor substrate container 12 of FIGS.1A and 1B, in accordance with some embodiments of the presentdisclosure. In some embodiments, purging starts at a time 314 and therelative humidity 302 drops below 10% level 306 at a time 312 in about50 seconds after the start of purging the FOUP with extreme clean dryair or inert gas. The relative humidity 302 drops below 1% level 308 inabout 180 seconds 310 after the start of the purge. In some embodimentsas shown in FIGS. 1A and 1B, after the start time 314 of the purge,while the door 15 is sealed, the extreme clean dry air or the inert gasis introduced to the semiconductor substrate container 12 via the gasinlet 20 and the gas purifier 40. After the start time 314 of the purge,the sensor 30 measures the relative humidity 302 of the gas that exitsthe gas outlet 25. As shown in the plot 300, the measured relativehumidity 302 initially increases and then decreases. In someembodiments, the process of purging the semiconductor substratecontainer 12 and controlling the gas purifier 40, sensor 30, andopening/closing the gas inlet 20 and the gas outlet 25 is performed bythe computer system 600 described in FIGS. 6A and 6B below.

FIGS. 4A and 4B illustrate the change in critical dimension of anexposed metal photoresist after storage in a FOUP without and withpurging the FOUP in accordance with some embodiments of the presentdisclosure. Plot 400 of FIG. 4A shows a mean CD value in nm on verticalcoordinate 402 versus a time 404 (storage time) the metal-containingphotoresist coated substrates are stored in the FOUP. As shown in theplot 400 of FIG. 4A, the metal-containing photoresist coated substratesstored in a FOUP after actinic radiation exposure without performing anextreme clean dry air or inert gas purge exhibit a steady degradation inthe critical dimension of the patterns in the developed photoresist. Asshown in the plot 400, after 25 minutes the mean CD value at point A1 is14.51 that may be assumed as the initial mean CD value. After 6 hoursthe mean CD value at point A2 is 14.07, after 12 hours the mean CD valueat point A3 drops to 13.68, after 24 hours the mean CD value at point A4decreases to 33.37, and after 48 hours the mean CD value at point A5 isdown to 12.77. Thus, after 48 hours of storage, photoresist-coatedsubstrates stored without purging suffer about a 12% degradation in themean critical dimension compared to the initial mean CD value. The meanCD values displayed in the plot 400 represent mean values of the CDsmeasured at multiple locations of a wafer or measured at multiplelocations of several wafers in the FOUP.

On the other hand, in some embodiments, metal-containing photoresistcoated substrates stored in a FOUP that has been purged with extremeclean dry air or inert gas after actinic radiation exposure do notexhibit a steady degradation in the critical dimension of the patternsin the developed photoresist. As shown in plot 450 of FIG. 4B, after 3minutes of storage the mean CD value at point B1 is 14.62 that may beassumed as the initial mean CD value. Also, after 12 hours the mean CDvalue at point B2 is 14.48, after 24 hours the mean CD value at point B3is 14.55, and alter 48 hours the mean CD value at point B4 is 14.70.Thus, after 48 hours of storage, the mean CD value of the substratesstored with purging is 14.70 had no appreciable change, less than 1%,compared to the initial mean CD value. As described, the mean CD valuesdisplayed in plot 450 represent mean values of the CDs measured atmultiple locations of a wafer or measured at multiple locations ofseveral wafers in the FOUP.

FIG. 5 illustrates a flow diagram of a process 500 for manufacturing asemiconductor device in accordance with some embodiments of the presentdisclosure. In operation S510, a photoresist layer is formed over asubstrate. In some embodiments, a metal-containing photoresist layer isdeposited on a wafer 27 of FIGS. 1A or 1B. In operation S520, thephotoresist layer on the substrate is selectively exposed to actinicradiation. In some embodiments, the photoresist layer is exposed to EUVradiation. In operation S530, the semiconductor substrate is stored in asemiconductor substrate container, e.g., the semiconductor substratecontainer 12 under an ambient of extreme dry clean air or an inert gas.In some embodiments, the semiconductor substrate container is a FOUP. Inoperation S540, after the storing, the photoresist layer is heated in apost-exposure bake. In some embodiments, the photoresist coatedsubstrate is baked at a temperature of about 50° C. to about 160° C. forabout 10 seconds to about 120 seconds during post-exposure hake.

FIGS. 6A and 6B illustrate an apparatus for purging the semiconductorsubstrate container of water vapor in accordance with some embodimentsof the present disclosure. FIG. 6A is a schematic view of a computersystem that controls the purging of a FOUP with extreme clean dry air orinert gas to remove the water vapor from the FOUP according to one ormore embodiments as described above. All of or a part, of the processes,method and/or operations of the foregoing embodiments can be realizedusing computer hardware and computer programs executed thereon. Theoperations include monitoring moisture and purging the semiconductorsubstrate container 12 (the FOUP). In FIG. 6A, a computer system 600 isprovided with a computer 601 including an optical disk read only memory(e.g., CD-ROM or DVD-ROM) drive 605 and a magnetic disk drive 606, akeyboard 602, a mouse 603, and a monitor 604, in some embodiments.

FIG. 6B is a diagram showing an internal configuration of the computersystem 600. In FIG. 6B. the computer 601 is provided with, in additionto the optical disk drive 605 and the magnetic disk drive 606, one ormore processors 611, such as a micro processing unit (MPU), a ROM 612 inwhich a program such as a boot up program is stored, a random accessmemory (RAM) 613 that is connected to the processor 611 and in which acommand of an application program is temporarily stored and a temporarystorage area is provided, a hard disk 614 in which an applicationprogram, a system program, and data are stored, and a bus 615 thatconnects the processor 611, the ROM 612, and the like. Note that thecomputer 601 may include a network card (not shown) for providing aconnection to a LAN.

The program tor causing the computer system 600 to execute the functionsof the purging water vapor from the FOUP in the foregoing embodimentsmay be stored in an optical disk 621 or a magnetic disk 622, which areinserted into the optical disk drive 605 or the magnetic disk drive 606,and transmitted to the hard disk 614. Alternatively, the program may betransmitted via a network (not shown) to the computer 601 and stored inthe hard disk 614. At the time of execution, the program is loaded intothe RAM 613. The program may be loaded from the optical disk 621 or themagnetic disk 622, or directly from a network. The program does notnecessarily have to include, for example, an operating system (OS) or athird party program to cause the computer 601 to execute the functionsof the photo mask data generating and merging apparatus in the foregoingembodiments. The program may only include a command portion to call artappropriate function (module) in a controlled mode and obtain desiredresults. In some embodiments, one of the processors 611 comprises acontroller.

In some embodiments, the photoresist layer is exposed to ultravioletradiation, such as deep ultraviolet radiation. In some embodiments, theultraviolet radiation is extreme ultraviolet radiation. In someembodiments, the radiation is an electron beam.

In some embodiments, the exposure radiation passes through a photomaskbefore irradiating the photoresist layer in some embodiments. In someembodiments, the photomask has a pattern to be replicated in thephotoresist layer. The pattern is formed by an opaque pattern on aphotomask substrate, in some embodiments. The opaque pattern may beformed by a material opaque to ultraviolet radiation, such as chromium,while the photomask substrate is formed of a material that istransparent to ultraviolet radiation, such as fused quartz. In someembodiments, the exposure radiation is reflected off of a photomask. Insome embodiments, the photomask includes a pattern of radiationreflective areas and absorbing areas.

The regions of the photoresist layer exposed to radiation undergo achemical reaction thereby changing their solubility in a subsequentlyapplied developer relative to the regions of the photoresist layer notexposed to radiation. In some embodiments, the portions of thephotoresist layer and protective layer exposed to radiation undergo acrosslinking reaction.

Next, the photoresist layer undergoes a post-exposure bake operation. Insome embodiments, the photoresist layer is heated to a temperature ofabout 50° C. and 160° C. for about 20 seconds to about 120 seconds. Thepost-exposure baking may be used in order to assist in the generating,dispersing, and reacting of an acid/base/free radical generated from theimpingement of the radiation upon the photoresist layer during theexposure. Such thermal assistance helps create or enhance chemicalreactions, which generate chemical differences between the exposedregions and the unexposed regions within the photoresist layer. Thesechemical differences also cause differences in the solubility betweenthe exposed region and the unexposed region.

The selectively exposed photoresist layer is subsequently developed byapplying a developer to the selectively exposed photoresist layer in adevelopment operation.

In some embodiments, the substrate includes a single crystallinesemiconductor layer on at least it surface portion. The substrate mayinclude a single crystalline semiconductor material such as, but notlimited to Si, Ge, SiGe, GaAs, InSb, GaP, GaSb, InAlAs, InGaAs, GaSbP,GaAsSb and InP. In some embodiments, the substrate is a silicon layer ofan SOI (silicon-on insulator) substrate. In certain embodiments, thesubstrate is made of crystalline Si.

The substrate may include in its surface region, one or more bufferlayers (not shown). The buffer layers can serve to gradually change thelattice constant from that of the substrate to that of subsequentlyformed source/drain regions. The buffer layers may be formed fromepitaxially grown single crystalline semiconductor materials such as,but not limited to Si, Ge, GeSn, SiGe, GaAs, InSb, GaP, GaSb, InAlAs,InGaAs, GaSbP, GaAsSb, GaN, GaP, and InP. In an embodiment, the silicongermanium (SiGe) buffer layer is epitaxially grown on the siliconsubstrate. The germanium concentration of the SiGe buffer layers mayincrease from 30 atomic% for the bottom-most, buffer layer to 70 atomic%for the top-most buffer layer.

In some embodiments, the substrate includes at least one metal, metalalloy, and metal/nitride/sulfide/oxide/silicide having the formulaMX_(a), where M is a metal and X is N, S, Se, O, Si, and a is from about0.4 to about 2.5. In some embodiments, the substrate includes titanium,aluminum, cobalt, ruthenium, titanium nitride, tungsten nitride,tantalum nitride, and combinations thereof.

In some embodiments, the substrate includes a dielectric having at leastsilicon, metal oxide, and metal nitride of the formula MX_(b), where Mis a metal or Si, X is N or O, and b ranges from about 0.4 to about 2.5.Ti, Al, Hf, Zr, and La are suitable metals, M, in some embodiments. Insome embodiments, the substrate includes silicon dioxide, siliconnitride, aluminum oxide, hafnium oxide, lanthanum oxide, andcombinations thereof.

In some embodiments, the photoresist layer is a photosensitive layerthat is patterned by exposure to actinic radiation. Typically, thechemical properties of the photoresist regions struck by incidentradiation change in a manner that depends on the type of photoresistused. Photoresist, layers are either positive tone resists or negativetone resists. Positive tone resist refers to a photoresist material thatwhen exposed to radiation (typically UV Sight) becomes soluble in adeveloper, while the region of the photoresist that is non-exposed (orexposed less) is insoluble in the developer. Negative tone resist, onthe other hand, refers to a photoresist material that when exposed toradiation becomes insoluble in the developer, while the region of thephotoresist that is non-exposed (or exposed less) is soluble in thedeveloper. The region of a negative tone resist that becomes insolubleupon exposure to radiation may become insoluble due to a cross-linkingreaction caused by the exposure to radiation.

Whether a photoresist is a positive tone or negative tone may depend onthe type of developer used to develop the resist. For example, somepositive tone photoresists provide a positive pattern, (i.e.—the exposedregions are removed by the developer), when the developer is anaqueous-based developer, such as a tetramethylammonium hydroxide (TMAH)solution. On the other hand, the same photoresist provides a negativepattern (i.e.—the unexposed regions are removed by the developer) whenthe developer is an organic solvent. Further, in some negative tonephotoresists developed with the TMAH solution, the unexposed regions ofthe photoresist are removed by the TMAH, and the exposed regions of thephotoresist, that undergo cross-linking upon exposure to actinicradiation, remain on the substrate after development.

In some embodiments, photoresists include a polymer resin along with oneor more photoactive compounds (PACs) in a solvent, in some embodiments.In some embodiments, the polymer resin includes a hydrocarbon structure(such as an alicyclic hydrocarbon structure) that contains one or moregroups that will decompose (e.g., acid labile groups or acid leavinggroups) or otherwise react when mixed with acids, bases, or freeradicals generated by the PACs (as further described below). In someembodiments, the hydrocarbon structure includes a repeating unit thatforms a skeletal backbone of the polymer resin. This repeating unit mayinclude acrylic esters, methacrylic esters, crotonic esters, vinylesters, maleic diesters, fumaric diesters, itaconic diesters,(meth)acrylonitrile, (meth)acrylamides, styrenes, vinyl ethers,combinations of these, or the like.

In some embodiments, the photoresist includes a polymer resin havingacid leaving groups selected from the following:

Specific structures that are utilized for the repealing unit of thehydrocarbon structure in some embodiments, include one or more of methylacrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butylacrylate, isobutyl acrylate, tert-butyl acrylate, n-hexyl acrylate,2-ethylhexyl acrylate, acetoxyethyl acrylate, phenyl acrylate,2-hydroxyethyl acrylate, 2-methoxyethyl acrylate, 2-ethoxyethylacrylate, 2-(2-methoxyethoxy)ethyl acrylate, cyclohexyl acrylate, benzylacrylate, 2-alkyl-2-adamantyl (meth)acrylate ordialkyl(1-adamantyl)methyl (meth)acrylate, methyl methacrylate, ethylmethacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butylmethacrylate, isobutyl methacrylate, tert-butyl methacrylate, n-hexylmethacrylate, 2-ethylhexyl methacrylate, acetoxyethyl methacrylate,phenyl methacrylate, 2-hydroxyethyl methacrylate, 2-methoxyethylmethacrylate, 2-ethoxyethyl methacrylate, 2-(2-methoxyethoxy)ethylmethacrylate, cyclohexyl methacrylate, benzyl methacrylate,3-chloro-2-hydroxypropyl methacrylate, 3-acetoxy-2-hydroxypropylmethacrylate, 3-chloroacetoxy-2-hydroxypropyl methacrylate, butylcrotonate, hexyl crotonate, or the like. Examples of the vinyl estersinclude vinyl acetate, vinyl propionate, vinyl butylate, vinylmethoxyacetate, vinyl benzoate, dimethyl maleate, diethyl maleate,dibutyl maleate, dimethyl fumarate, diethyl fumarate, dibutyl fumarate,dimethyl itaconate, diethyl itaconate, dibutyl itaconate, acrylamide,methyl acrylamide, ethyl acrylamide, propyl acrylamide, n-butylacrylamide, tert-butyl acrylamide, cyclohexyl acrylamide, 2-methoxyethylacrylamide, dimethyl acrylamide, diethyl acrylamide, phenyl acrylamide,benzyl acrylamide, methacrylamide, methyl methacrylamide, ethylmethacrylamide, propyl methacrylamide, n-butyl methacrylamide,tert-butyl methacrylamide, cyclohexyl methacrylamide, 2-methoxyethylmethacrylamide, dimethyl methacrylamide, diethyl methacrylamide, phenylmethacrylamide, benzyl methacrylamide, methyl vinyl ether, butyl vinylether, hexyl vinyl ether, methoxyethyl vinyl ether, dimethylaminoethylvinyl ether, or the like. Examples of styrenes include styrene, methylstyrene, dimethyl styrene, trimethyl styrene, ethyl styrene, isopropylstyrene, butyl styrene, methoxy styrene, butoxy styrene, acetoxystyrene, chloro styrene, dichloro styrene, bromo styrene, vinyl methylbenzoate, α-methyl styrene, maleimide, vinylpyridine, vinylpyrrolidone,vinylcarbazole, combinations of these, or the like.

In some embodiments, the repeating unit of the hydrocarbon structurealso has either a monocyclic or a polycyclic hydrocarbon structuresubstituted into it, or the monocyclic or polycyclic hydrocarbonstructure is the repeating unit, in order to form an alicyclichydrocarbon structure. Specific examples of monocyclic structures insome embodiments include bicycloalkane, tricycloalkane,tetracycloalkane, cyclopentane, cyclohexane, or the like. Specificexamples of polycyclic structures in some embodiments includeadamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane,or the like.

The group which will decompose is attached to the hydrocarbon structureso that, it will react with the acids/bases/free radicals generated bythe PACs during exposure. Groups that react with acids are known asacid-labile groups. In some embodiments, the group which will decomposeis a carboxylic acid group, a fluorinated alcohol group, a phenolicalcohol group, a sulfonic group, a sulfonamide group, a sulfonylimidogroup, an (alkylsulfonyl) (alkylcarbonyl)methylene group, an(alkylsulfonyl)(alkyl-carbonyl)imido group, abis(alkylcarbonyl)methylene group, a bis(alkylcarbonyl)imido group, abis(alkylsylfonyl)methylene group, a bis(alkylsulfonyl)imido group, atris(alkylcarbonyl methylene group, a tris(alkylsulfonyl)ethylene group,combinations of these, or the like. Specific groups that are used torthe fluorinated alcohol group include fluorinated hydroxyalkyl groups,such as a hexafluoroisopropanol group in some embodiments. Specificgroups that are used for the carboxylic acid group include acrylic acidgroups, methacrylic acid groups, or the like.

In some embodiment, the acid-labile group (ALG) decomposes by the actionof the acid generated by the photo-acid generator leaving a carboxylicacid group pendant to the polymer resin chain, as shown in the ALGde-protect reaction:

In some embodiments, the polymer resin also includes other groupsattached to the hydrocarbon structure that help to improve a variety ofproperties of the polymerizable resin. For example, inclusion of alactone group to the hydrocarbon structure assists to reduce the amountof line edge roughness after the photoresist has been developed, therebyhelping to reduce the number of defects that occur during development.In some embodiments, the lactone groups include rings having five toseven members, although any suitable lactone structure may alternativelybe used for the lactone group.

In some embodiments, the polymer resin includes groups that can assistin increasing the adhesiveness of the photoresist layer to underlyingstructures (e.g., substrate). Polar groups may be used to help increasethe adhesiveness. Suitable polar groups include hydroxyl groups, cyanogroups, or the like, although any suitable polar group may,alternatively, be used.

Optionally, the polymer resin includes one or more alicyclic hydrocarbonstructures that do not also contain a group which will decompose in someembodiments. In some embodiments, the hydrocarbon structure that doesnot contain a group which will decompose includes structures such as1-adamanty(meth)acrylate, tricyclodecanyl (meth)acrylate, cyclohexyl(methacrylate), combinations of these, or the like.

Additionally, some embodiments of the photoresist include one or morephotoactive compounds (PACs). The PACs are photoactive components, suchas photo-acid generators, photo base generators, free-radicalgenerators, or the like. The PACs may be positive-acting ornegative-acting. In some embodiments in which the PACs are a photo-acidgenerator, the PACs include halogenated triazines, onium salts,diazonium salts, aromatic diazontum salts, phosphonium salts, sulfoniumsalts, iodonium salts, imide sulfonate, oxime sulfonate, diazodisulfone,disulfone, o-nitrobenzylsuifonate, sulfonated esters, halogenatedsulfbnyloxy dicarboximides, diazodisuifones, α-cyanooxyamine-sulfonates,imidesulfonates, ketodiazosulfones, sulfonyldiazoesters,1,2-di(arylsulfonyl)hydrazine3, nitrobenzyi esters, and the s-triazinederivatives, combinations of these, or the like.

Specific examples of photo-acid generators includeα-(trifluoromethylsulfonyloxy)-bicyclo[2.2.1]hept-5-ene-2,3-dicarb-o-ximide(MDT), N-hydroxy-naphthalimide (DDSN), benzoin tosylate,t-butylphenyl-α-(p-toluenesulfonyloxy)-acetate andt-butyl-α-(p-toluenesulfonyloxy)-acetate, triarylsulfonium anddiaryliodonium hexafluoroantimonates, hexafluoroarsenates,trifluoromethanesulfonates, iodonium perfluorooctanesulfonate,N-camphorsulfonyloxynaphthalimide,N-pentafluorophenylsulfonyloxynaphthalimide, ionic iodonium sulfonatessuch as diaryl iodonium (alkyl or aryl)sulfonate andbis-(di-t-butylphenyl)iodonium camphanylsulfonate,perfluoroalkanesulfonates such as perfluoropentanesulfonate,perfluorooctanesulfonate, perfluoromethanesulfonate, aryl (e.g., phenylor benzyl)triflates such as triphenylsulfonium triflate orbis-(t-butylphenyl)iodonium triflate; pyrogallol derivatives (e.g.,trimesylate of pyrogallol), trilluoromethanesulfonate esters ofhydroxyimides, α,α′-bis-sulfonyl-diazomethanes, sulfonate esters ofnitro-substituted benzyl alcohols, naphthoquinone-4-diazides, alkyldisulfones, or the like.

Structures of photo-acid generators according to the embodiments of thedisclosure include;

In some embodiments in which the PACs are free-radical generators thePACs include n-phenylglycine: aromatic ketones, including benzophenone,N,N′-tetramethyl-4,4′-diaminobenzophenone, diaminobenzophenone,N,N′-tetraethyl-4,4′-diaminobenzophenone,4-methoxy-4′-dimethylaminobenzo-phenone,3,3′-dimethyl-4-methoxybenzophenone,p,p′-bis(dimethylamino)benzo-phenone,p,p′-bis(dimethylamino)-benzophenone; anthraquinone,2-ethylanthraquinone; naphthaquinone; and phenanthraquinone; benzoinsincluding benzoin, benzoinmethylether, benzoinisopropyiether,benzoin-n-butylether, benzoin-pheny lether, methylbenzoin andethylbenzoin; benzyl derivatives, including dibenzyl,benzyldiphenyldisulfide, and benzyldimethylketal; acridine derivatives,including 9-phenylacridine, and 1,7-bis(9-acridinyl)heptane;thioxanthones, including 2-chlorothioxanthone, 2-methylthioxanthone,2,4-diethylthioxanthone, 2,4-dimethylthioxanthone, and2-isopropylthioxanthone; acetophenones, including1,1-dichloroacetophenone, p-t-butyldichloro-acetophenone,2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, and2,2-dichioro-4-phenoxyacetophenone; 2,4,5-triarylimidazole dimers,including 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer,2-(o-chlorophenyl)-4,5-di-(m-methoxyphenyl imidazole dimer,2-(o-fluorophenyl)-4,5-diphenylimidazole dimer,2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer,2-(p-methoxypbenyl)-4,5-diphenylimidazole dimer,2,4-di(p-methoxyphenyl)-5-phenylimidazole dimer,2-(2,4-dimethoxyphenyl)-4,5-diphenylimidazole dimer and2-(p-methylmercaptophenyl)-4,5-diphenylimidazole dimmer; combinations ofthese, or the like.

In some embodiments in which the PACs are photobase generators, the PACsincludes quaternary ammonium dithiocarbamates, a aminoketones,oxime-urethane containing molecules such as dibenzophenoneoximehexamethylene diurethan, ammonium tetraorganyiborate salts, andN-(2-nitrobenzyloxycarbonyl)cyclic amines, combinations of these, or thelike.

As one of ordinary skill in the art will recognize, the chemicalcompounds listed herein are merely intended as illustrated examples ofthe PACs and are not intended to limit the embodiments to only thosePACs specifically described. Rather, any suitable PAC may be used, andall such PACs are fully intended to be included within the scope of thepresent embodiments.

In some embodiments, a cross-linking agent is added to the photoresist.The cross-linking agent reacts with one group from one of thehydrocarbon structures in the polymer resin and also reacts with asecond group from a separate one of the hydrocarbon structures in orderto cross-link and bond the two hydrocarbon structures together. Thisbonding and cross-linking increases the molecular weight of the polymerproducts of the cross-linking reaction and increases the overall linkingdensity of the photoresist. Such an increase in density and linkingdensity helps to improve the resist pattern.

In some embodiments the cross-linking agent has the following structure:

such that C is carbon, n ranges from 1 to 15; A and B independentlyinclude a hydrogen atom, a hydroxyl group, a halide, an aromatic carbonring, or a straight or cyclic alkyl, alkoxyl/fluoro, alkyl/fluoroalkoxylchain having a carbon number of between 1 and 12, and each carbon Ccontains A and B; a first terminal carbon C at a first end of a carbon Cchain includes X and a second terminal carbon C at a second end of thecarbon chain includes Y, such that X and Y independently include anamine group, a thiol group, a hydroxyl group, an isopropyl alcoholgroup, or an isopropyl amine group, except when n=1 then X and Y arebonded to the same carbon C. Specific examples of materials that may beused as the cross-linking agent, include the following:

Alternatively, instead of or in addition to the cross-linking agentbeing added to the photoresist composition, a coupling reagent is addedin some embodiments, in which the coupling reagent is added in additionto the cross-linking agent. The coupling reagent assists thecross-linking reaction by reacting with the groups on the hydrocarbonstructure in the polymer resin before the cross-linking reagent,allowing for a reduction in the reaction energy of the cross-linkingreaction and an increase in the rate of reaction. The bonded couplingreagent then reacts with the cross-linking agent, thereby coupling thecross-linking agent to the polymer resin.

Alternatively, in some embodiments in which the coupling reagent isadded to the photoresist without the cross-linking agent, the couplingreagent is used to couple one group from one of the hydrocarbonstructures in the polymer resin to a second group from a separate one ofthe hydrocarbon structures in order to cross-link and bond the twopolymers together. However, in such an embodiment the coupling reagent,unlike the cross-linking agent, does not remain as past of the polymer,and only assists in bonding one hydrocarbon structure directly toanother hydrocarbon structure.

In some embodiments, the coupling reagent has the following structure:

where R is a carbon atom, a nitrogen atom, a sulfur atom, or an oxygenatom; M includes a chlorine atom, a bromine atom, an iodine atom, —NO₂;—SO₃; —H—; —CN; —NCO, —OCN; —CO₂—; —OH; —OR*, —OC(O)CR*; —SR,—SO2N(R*)₂; —SO2R*; SOR; —OC(O)R*; —C(O)OR*; —C(O)R*; —Si(OR*)₃;—Si(R*)₃; epoxy groups, or the like; and R* is a substituted orunsubstituted C1-C12 alkyl, C1-C12 aryl, C1-C12 aralkyl, or the like.Specific examples of materials used as the coupling reagent in someembodiments include the following:

In some embodiments, the solvent is an organic solvent, and includes oneor more of any suitable solvent such as ketones, alcohols, polyalcohols,ethers, glycol ethers, cyclic ethers, aromatic hydrocarbons, esters,propionates, lactates, lactic esters, alkylene glycol monoalkyl ethers,alkyl lactates, alkyl alkoxypropionates, cyclic lactones, monoketonecompounds that contain a ring, alkylene carbonates, alkvl alkoxyacetate,alkyl pyruvates, lactate esters, ethylene glycol alkyl ether acetates,diethylene glycols, propylene glycol alkyl ether acetates, alkyleneglycol alkyl, ether esters, alkylene glycol monoalkyl esters, or thelike;

Specific examples of materials that may be used as the solvent for thephotoresist include, acetone, methanol, ethanol, toluene, xylene,4-hydroxy-4-methyl-2-pentatone, tetrahydrofuran, methyl ethyl ketone,cyclohexanone, methyl isoamyl ketone, 2-heptanone, ethylene glycol,ethylene glycol monoacetate, ethylene glycol dimethyl ether, ethyleneglycol dimethyl ether, ethylene glycol methyl ethyl ether, ethyleneglycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolveacetate, diethylene glycol, diethylene glycol monoacetate, diethyleneglycol monomethyl ether, diethylene glycol diethyl ether, diethyleneglycol dimethyl ether, diethylene glycol ethylmethyl ether,diethethylene glycol monoethvl ether, diethylene glycol monobutyl ether,ethyl 2-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, ethyl2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate,methyl 2-hydroxy-2-methylbutanate, methyl 3-methoxypropionate, ethyl3-methoxypropionate, methyl 3-ethoxypropionate, ethyl3-ethoxypropionate, methyl acetate, ethyl acetate, propyl acetate, butylacetate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate,propylene glycol, propylene glycol monoacetate, propylene glycolmonoethyl ether acetate, propylene glycol monomethyl ether acetate,propylene glycol monopropyl methyl ether acetate, propylene glycolmonobutyl ether acetate, propylene glycol monobtrtyl ether acetate,propylene glycol monomethyl ether propionate, propylene glycol monoethylether propionate, propylene glycol methyl ether acetate, propyleneglycol ethyl ether acetate, ethylene glycol monomethyl ether acetate,ethylene glycol monoethyl ether acetate, propylene glycol monomethylether, propylene glycol monoethyl ether, propylene glycol monopropylether, propylene glycol monobutyl ether, ethylene glycol monomethylether, ethylene glycol monoethyl ether, ethyl 3-ethoxypropionate, methyl3-methoxyproplonate, methyl 3-ethoxypropionate, and ethyl3-methoxypropionate, β-propiolactone, β-butyrolactone, γ-butyrolactone,α-methyl-γ-butyrolactone, β-methyl-γ-butyrolactone, γ-valerolactone,γ-caprolactone, γ-octanoic lactone, α-hydroxy-γ-butyrolactone,2-butanone, 3-methylbutanone, pinacolone, 2-pentanone, 3-pentanone,4-methyl-2-pentanone, 2-methyl-3-pentanone, 4,4-dimethyl-2-pentanone,2,4-dimethyl-3-pentanone, 2,2,4,4-tetramethyl-3-pentanone, 2-hexanone,3-hexanone, 5-methyl-3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone,2-methyl-3-heptanone, 5-methyl-3-heptanone, 2,6-dimethyl-4-heptanone,2-octanone, 3-oetanone, 2-nonanone, 3-nonanone, 5-nonanone, 2-decanone,3-decanone, 4-decanone, 5-hexene-2-one, 3-pentene-2-one, cyclopentanone,2-methylcyclopentanone, 3-methylcyclopentanone,2,2-dimethylcyclopentanone, 2,4,4-trimethylcyclopentanone,cyclohexanone, 3-methylcyclohexanone, 4-methylcyclohexanone,4-ethyleyclohexanone, 2,2-dimethylcyclohexanone,2,6-dimethylcyclohexanone, 2,2,6-trimethylcyclohexanone, cycloheptanone,2-methylcycloheptanone, 3-methylcycloheptanone, propylene carbonate,vinylene carbonate, ethylene carbonate, butylene carbonate,acetate-2-methoxyethyl, acetate-2-ethoxyethyl,acetate-2-(2-ethoxyethoxy)ethyl, acetate-3-methoxy-3-methylbutyl,acetate-1-methoxy-2-propyl, dipropylene glycol, monomethylether,monoethylether, monopropylether, monobutylether, monophenylether,dipropylene glycol monoacetate, dioxane, methyl pyruvate, ethylpyruvate, propyl pyruvate, methyl methoxypropionate, ethylethoxypropionate, n-methylpyrrolidone (NMP), 2-methoxyethyl ether(diglyme), ethylene glycol monomethyl ether, propylene glycol monomethyiether, methyl propionate, ethyl propionate, ethyl ethoxy propionate,methylethyl ketone, cyclohexanone, 2-heptanone, cyclopentanone,cyclohexanone, ethyl 3-ethoxypropionate, propylene glycol methyl etheracetate (PGMEA), methylene cellosolve, 2-ethoxyethanol,N-methylformamide, N,N-dimethylformamide, N-methylformamide,N-methylacetamide, N,N-dimethylacetamide, dimethylsulfoxide, benzylethyl ether, dihexyl ether, acetonylacetone, isophorone, caproic acid,captylic acid, 1-octanol, 1-nonanol, benzyl alcohol, benzyl acetate,ethyl benzoate, diethyl oxalate, diethyl maleate, phenyl cellosolveacetate, or the like.

As one of ordinary skill in the art will recognize, the materials listedand described above as examples of materials that may be used for thesolvent component of the photoresist axe merely illustrative and are notintended to limit the embodiments. Rather, any suitable materials thatdissolve the polymer resin and the PACs may be used to help mix andapply the photoresist. All such materials are fully intended to beincluded within the scope of the embodiments.

Additionally, while individual ones of the above described materials maybe used as the solvent for the photoresist and protective polymer, inother embodiments more than one of the above described materials areused. For example, in some embodiments, the solvent includes acombination mixture of two or more of the materials described. All suchcombinations axe fully intended to be included within the scope of theembodiments.

In addition to the polymer resins, the PACs, the solvents, thecross-linking agent, and the coupling reagent, some embodiments of thephotoresist also includes a number of other additives that assist thephotoresist to obtain high resolution. For example, some embodiments ofthe photoresist also includes surfactants in order to help improve theability of the photoresist to coat the surface on which it is applied.

Another additive added to some embodiments of the photoresistcomposition and protective layer composition is a quencher, whichinhibits diffusion of the generated acids/bases/free radicals within thephotoresist. The quencher improves the resist pattern configuration aswell as the stability of the photoresist over time. In some embodiments,the quencher is a photo decomposed base. In some embodiments, an organicacid is used as the quencher.

Another additive added to some embodiments of the photoresist is astabilizer, which assists in preventing undesired diffusion of the acidsgenerated during exposure of the photoresist. Another additive in someembodiments of the photoresist is a dissolution inhibitor to helpcontrol dissolution of the photoresist during development. Anotheradditive in sorne embodiments of the photoresist is a pilasticizer.Plasticizers may be used to reduce deiainination and cracking betweenthe photoresist and underlying layers (e.g., the layer to be patterned).A coloring agent is another additive included in some embodiments of thephotoresist. The coloring agent observers examine the photoresist andfmd any defects that may need to be remedied prior to furtherprocessing. Adhesion additives are added to some embodiments of thephotoresist to promote adhesion between the photoresist and anunderlying layer upon which the photoresist has been applied (e.g., thelayer to be patterned). Surface leveling agents arc added to someembodiments of the photoresist to assist a top surface of thephotoresist to be level, so that impinging light will not be adverselymodified by an unlevel surface.

Some embodiments of the photoresist include metal oxide nanoparticles.In some embodiments, the photoresist includes one or more metal oxidesnanopartides selected from the group consisting of titanium dioxide,zinc oxide, zirconium dioxide, nickel oxide, coball oxide, manganeseoxide, copper oxides, iron oxides, strontium titanate, tungsten oxides,vanadium oxides, chromium oxides, tin oxides, hafnium oxide, indiumoxide, cadmium oxide, molybdenum oxide, tantalum oxides, niobium oxide,aluminum oxide, and combinations thereof. As used herein, nanoparticlesare particles having an average particle size between about 1 and about10 nm. In some embodiments, the metal oxide nanoparticles have anaverage particle size between about. 2 and about 5 nm. In someembodiments, the amount of metal oxide nanopartides in the photoresistcomposition ranges from about 0.1 wt. % to about 20 wt. % based on thetotal weight of the photoresi st composition. In some embodiments, theamount of nanoparticles in the photoresist composition ranges from about1 wt. % to about 10 wt. % based on the total weight of the photoresistcomposition. In some embodiments, the amount of metal oxide nanopartidesin the photoresist composition ranges from about 1 wt. % to about 15 wt.% based on the weight of the first solvent. In some embodiments, theamount of nanoparticles in the photoresist composition ranges from about5 wt. % to about 10 wt. % based on the weight of the first solvent.Below about 1 wt. % metal oxide nanoparticles the photoresist coating istoo thin. Above about 15 wt. % metal oxide nanopartides the photoresistcoating is too thick.

In some embodiments, the metal oxide nanopartides are completed with aligand. In some embodiments, the ligand is a carboxyiic add or sulfonicacid ligand. For example, in some embodiments, zirconium oxide orhafnium oxide nanopartides are complexed with methacrylic acid forminghafnium methacrylic acid (HfMAA) or zirconium methacrylic acid (ZrMAA).In some embodiments, the metal oxide nanoparticles are eomplexed withligands including aliphatic or aromatic groups. The aliphatic oraromatic groups may be unbranched or branched with cyclic or noncyciicsaturated pendant groups containing 1-9 carbons, including alkyl groups,alkenyl groups, and phenyl groups. The branched groups may be furthersubstituted with oxygen or halogen.

In some embodiments, the photoresist composition includes about 0.1 wt.% to about 20 wt. % of the ligand. In some embodiments, the photoresistincludes about 1 wt. % to about 10 wt. % of the ligand. In someembodiments, the ligand is HfMAA or ZrMAA dissolved at about a 5 wt. %to about 10 wt. % weight range in a coating solvent, such as propyleneglycol methyl ether acetate (PGMEA).

Embodiments of the present disclosure provide greater flexibility in thesemiconductor device manufacturing process because after thephotolithographic exposure step metal-containing photoresist coatedsubstrates do not have to undergo post-exposure bake immediately afterexposure to actinic radiation. Furthermore, the semiconductormanufacturing line does not have to be configured so that that actinicradiation exposed photoresist coated substrates am routed directly intoa post-exposure bake tool. Embodiments of the present disclosure provideincreased wafer per hour throughput over conventional manufacturingmethods. In addition, the methods according to the present disclosureprovide improved control of the critical dimension of the photoresistpattern and storing the substrates in extreme clean dry air or inert gasreduces impurities that may form on the photoresist surface.

According to some embodiments of the present disclosure, a method formanufacturing a semiconductor device includes forming a photoresistlayer over a semiconductor substrate. The photoresist layer isselectively exposed to actinic radiation. After selectively exposing thephotoresist layer to actinic radiation, the semiconductor substrate isstored in a semiconductor substrate container under an ambient ofextreme dry clean air or inert gas. After the storing the semiconductorsubstrate, a first heating of the photoresist layer is performed. In anembodiment, the first heating of the photoresist layer is at atemperature of 50° C. to 160° C. In an embodiment, the photoresist layercomprises a metal-containing photoresist. In an embodiment, the actinicradiation is ultraviolet, deep ultraviolet, extreme ultraviolet,electron beam, or ion beam. In an embodiment, the extreme dry clean airor the inert, gas contains less than I ppb impurity. In an embodiment,the semiconductor substrate container is a front, opening unified pod.In an embodiment, the method includes purging the semiconductorsubstrate container with the extreme dry clean air or the inert gasafter the semiconductor substrate is placed in trie semiconductorsubstrate container and sealing the semiconductor substrate containerafter the purging. In an embodiment, the method includes monitoring amoisture content of a gas exiting the semiconductor substrate containerduring purging. In an embodiment, the method includes stopping thepurging and sealing the semiconductor substrate container when arelative humidity of the gas exiting the semiconductor substratecontainer is below a threshold relative humidity. In art embodiment, thethreshold relative humidity is between 0.1% to 1% relative humidity. Inan embodiment, a duration of the storing is between 1 minute and 96hours. In an embodiment, the method includes developing the selectivelyexposed photoresist layer after the first heating. In an embodiment, themethod includes forming a first protective layer over the semiconductorsubstrate before forming the photoresist layer, removing the fustprotective layer after forming the photoresist layer, and forming asecond protective layer over the semiconductor substrate after the firstheating.

According to some embodiments of the present disclosure, a method formanufacturing a semiconductor device includes forming a photoresistiayer over a semiconductor substrate. The photoresist layer isselectively exposed to extreme ultraviolet, radiation. After selectivelyexposing the photoresist layer to extreme ultraviolet radiation, thesemiconductor substrate is stored in a semiconductor substrate containerunder an ambient of extreme dry clean air or an inert gas with arelative humidity between 0.1% to 1%. After the storing thesemiconductor substrate for a period between 12 hours and 48 hours, apost-exposure bake of the photoresist layer is performed.

According to some embodiments of the present disclosure, a storagesystem for storing photoresist coated semiconductor substrates includesa semiconductor substrate container configured to store a plurality ofsemiconductor substrates, a gas inlet, a gas outlet, and a sensor. Thesensor is coupled to the gas outlet and configured to measure a humidityof a gas exiting the semiconductor substrate container through, the gasoutlet, and a source of an inert gas or an extreme clean dry airconnected via a gas purifier to the gas inlet. A controller isconfigured to control the gas purifier and the sensor to purge ahumidity inside the semiconductor substrate container with the inert gasor the extreme clean dry air such that a relative humidity of the gasexiting the semiconductor substrate container is below a thresholdrelative humidity. In an embodiment, the storage system thesemiconductor substrate container is a front opening unified pod. In anembodiment, the threshold relative humidity is between 0.1% relativehumidity to 1% relative humidity. In an embodiment, the storage systemincludes a gas purifier connected in line with the gas inlet. In anembodiment, the gas purifier is an automatically regenerable purifier.In an embodiment, the gas purifier is configured to provide purified gascontaining less than 1 ppb impurities and less than 1% relativehumidity.

The foregoing outlines features of several embodiments or examples sothat those skilled in the art rnay better understand the aspects of thepresent disclosure. Those skilled in the art should appreciate that theymay readily use the present disclosure as a basis for designing ormodifying other processes and structures for carrying out the samepurposes and/or achieving the same advantages of the embodiments orexamples introduced herein. Those skilled in the art should also realizethat such equivalent constructions do not depart from the spirit andscope of the present disclosure, and that they may make various changes,substitutions, and alterations herein without departing from the spiri tand scope of the presen t disclosure.

What is claimed is:
 1. A storage system for storing photoresist coated semiconductor substrates, comprising: a semiconductor substrate container configured to store a plurality of semiconductor substrates; a gas inlet; a gas outlet; a sensor coupled to the gas outlet and configured to measure a humidity of a gas exiting the semiconductor substrate container through the gas outlet; a source of an inert gas or an extreme clean dry air connected via a gas purifier to the gas inlet; and a controller configured to control the gas purifier and the sensor to purge a humidity inside the semiconductor substrate container with the inert gas or the extreme clean dry air such that a relative humidity of the gas exiting the semiconductor substrate container is below a threshold relative humidity.
 2. The storage system of claim 1, wherein the semiconductor substrate container is a front opening unified pod.
 3. The storage system of claim 1, wherein the threshold relative humidity is between 0.1% relative humidity to 1% relative humidity.
 4. The storage system of claim 1, wherein the gas purifier is an automatically regenerable purifier.
 5. The storage system of claim 1, wherein the gas purifier is configured to provide purified gas containing less than 1 ppb impurities and less than 1% relative humidity.
 6. The storage system of claim 1, wherein the semiconductor substrate container is configured to maintain an internal pressure of 130 kPa.
 7. The storage system of claim 1, wherein the controller is configured to monitor moisture of the gas exiting the semiconductor substrate container.
 8. The storage system of claim 1, wherein the gas inlet and gas outlet are configured to be sealed when the relative humidity of the gas exiting the semiconductor substrate container is below a threshold relative humidity.
 9. The storage system of claim 1, wherein a door of semiconductor substrate is configured to be sealed when the relative humidity of the gas exiting the semiconductor substrate container is below a threshold relative humidity.
 10. A storage system, comprising: a front opening unified pod; an inert gas source or an extreme clean dry air source coupled to the front opening unified pod via a gas inlet; a gas outlet coupled to the front opening unified pod; a humidity sensor coupled to the gas outlet; and a controller configured to monitor a relative humidity of a gas exiting the gas outlet and control the relative humidity of the gas exiting the front opening pod to below a threshold relative humidity.
 11. The storage system of claim 10, wherein the threshold relative humidity is between 0.1% relative humidity to 1% relative humidity.
 12. The storage system of claim 10, further comprising a gas purifier coupled to the gas inlet.
 13. The storage system of claim 12, wherein the gas purifier is an automatically regenerable purifier.
 14. The storage system of claim 12, wherein the gas purifier is configured to provide purified gas to the gas inlet containing less than 1 ppb impurities and less than 1% relative humidity.
 15. The storage system of claim 10, wherein the front opening unified pod is configured to maintain an internal pressure of 130 kPa.
 16. The storage system of claim 10, wherein the gas inlet and gas outlet are configured to be sealed when the relative humidity of the gas exiting the front opening unified pod is below a threshold relative humidity.
 17. The storage system of claim 10, wherein the gas inlet and the gas outlet are coupled to a bottom of the front opening unified pod.
 18. A storage system, comprising: a front opening unified pod; a gas inlet coupled to the front opening unified pod; a gas purifier coupled to the gas inlet; an inert gas source or an extreme clean dry air source coupled to the front opening unified pod via the gas purifier and the gas inlet; a gas outlet coupled to the front opening unified pod; a humidity sensor coupled to the gas outlet; and a controller configured to monitor a relative humidity of a gas exiting the gas outlet and configured to control the inert gas source or extreme dry air source, the gas purifier, the gas inlet, and the gas outlet to maintain the relative humidity of the gas exiting the semiconductor substrate container to below a threshold relative humidity.
 19. The storage system of claim 18, wherein the threshold relative humidity is between 0.1% relative humidity to 1% relative humidity.
 20. The storage system of claim 18, wherein the gas purifier is configured to provide purified gas to the gas inlet containing less than 1 ppb impurities and less than 1% relative humidity. 